The present invention relates to a method for preparing surfactants, and especially succinimide dispersants which are useful as lubricant additives.
Surfactants encompass a well-known and wide variety of surface active agents with numerous uses in industry and commerce. Among the commercially important surfactants are those commonly known as dispersants. These materials have been known and used for many years in the lubricants industry for the purpose of dispersing sludge and other contaminants that can develop in engine oils.
Surfactants generally comprise a polar xe2x80x9cheadxe2x80x9d portion and a non-polar xe2x80x9ctail.xe2x80x9d In many instances the head and tail portions, or parts of them, need to be combined chemically to produce the final product, and this combination may involve the physical mixing of relatively polar and relatively non-polar reactants. It has now been found that the completeness and efficiency of the physical mixing, which may occur at the time of or just prior to the beginning of the reaction of the components, can have important effects on the physical and chemical properties of the final product. Thus, certain surfactants such as nitrogen-containing dispersants have been found to have improved properties of clarity, ease of filterability, and compatibility when they are prepared using the premixing technology of the present invention.
U.S. Pat. No. 5,073,600, Gorman et al., Dec. 17, 1991, discloses dispersant viscosity index improvers and a process of functionalizing a base polymer by grafting alpha-beta unsaturated carboxylic acid, anhydride, or ester to a base polymer. The grafting is performed in a blending device capable of imparting high mechanical energy. As the polymer with the carboxylic acid functionality grafted to it, diluent, and free radical initiator continue to move through the blending apparatus (e.g., an extruder), the blend is next contacted with an amine which is introduced into the extruder through a line. The reaction between the amine and the acid functionality which is grafted onto the polymer occurs within a reaction zone (i.e., within the extruder).
U.S. Pat. No. 5,624,999, Lombardi et al, Apr. 29, 1997, discloses an ashless dispersant prepared from reactants in different phases by reacting the reactants in a reaction region defined by adjacent surfaces between which there is relative movement or on a thin film on a surface over which they move.
The present invention provides a method for synthesizing a surfactant from an amine or alcohol and a hydrocarbyl-substituted succinic acylating agent, comprising: feeding the amine into a stream comprising the hydrocarbyl substituted succinic acylating agent, to form a combined stream; passing said combined stream through an in-line mixer so as to effect premixing and initial reaction of the components; and thereafter passing the combined stream into at least one reactor, wherein said combined stream is further processed to form said surfactant.
The invention similarly provides a method for synthesizing a surfactant from water and a hydrocarbyl-substituted succinic anhydride, comprising: feeding the water into a stream comprising the hydrocarbyl substituted succinic anhydride, to form a combined stream; passing said combined stream through an in-line mixer so as to effect premixing and initial reaction of the components; and thereafter passing the combined stream into at least one reactor, wherein said combined stream is further processed to form said surfactant.